Electrical plug for a medical device

ABSTRACT

A dialysis machine comprising: a power supply for providing power to the dialysis machine, the power supply including a power supply cable that includes a first ground wire electrically connected to a first ground prong; and a hydraulics system for making dialysate, supplying the dialysate to a dialysate circuit, and draining spent dialysate from the dialysate circuit, the hydraulics system including a hydraulics grounding cable that includes a second ground wire electrically connected to a second ground prong.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of and claims the benefitof priority under 35 U.S.C. § 120 to U.S. application Ser. No.16/686,920, filed Nov. 18, 2019, now U.S. Pat. No. 11,303,075, which isa divisional of U.S. application Ser. No. 15/404,725, filed Jan. 12,2017, now U.S. Pat. No. 10,512,715, the entire contents of which arehereby incorporated by reference.

TECHNICAL FIELD

This disclosure relates to an electrical plug for a dialysis machine.

BACKGROUND

Dialysis is a treatment used to support a patient with insufficientrenal function. The two principal dialysis methods are hemodialysis andperitoneal dialysis. During hemodialysis (“HD”), the patient's blood ispassed through a dialyzer of a dialysis machine while also passing adialysis solution or dialysate through the dialyzer. A semi-permeablemembrane in the dialyzer separates the blood from the dialysate withinthe dialyzer and allows diffusion and osmosis exchanges to take placebetween the dialysate and the blood stream. These exchanges across themembrane result in the removal of waste products, including solutes likeurea and creatinine, from the blood. These exchanges also regulate thelevels of other substances, such as sodium and water, in the blood. Inthis way, the dialysis machine acts as an artificial kidney forcleansing the blood.

During peritoneal dialysis (“PD”), the patient's peritoneal cavity isperiodically infused with dialysate. The membranous lining of thepatient's peritoneum acts as a natural semi-permeable membrane thatallows diffusion and osmosis exchanges to take place between thesolution and the blood stream. These exchanges across the patient'speritoneum result in the removal of waste products, including soluteslike urea and creatinine, from the blood, and regulate the levels ofother substances, such as sodium and water, in the blood.

SUMMARY

In one aspect, a dialysis machine includes a power supply for providingpower to the dialysis machine. The power supply includes a power supplycable that includes a first ground wire electrically connected to afirst ground prong. The dialysis machine also includes a hydraulicssystem for making dialysate, supplying the dialysate to a dialysatecircuit, and draining spent dialysate from the dialysate circuit. Thehydraulics system includes a hydraulics grounding cable that includes asecond ground wire electrically connected to a second ground prong.

Implementations can include one or more of the following features.

In some implementations, the first ground wire and the first groundprong form a first grounding connection, and the second ground wire andthe second ground prong form a second grounding connection.

In some implementations, the first grounding connection is separate anddistinct from the second grounding connection.

In some implementations, the power supply cable and the hydraulicsgrounding cable are connected to a combined plug that is configured toplug into an AC power outlet.

In some implementations, the combined plug includes a line prong that iselectrically connected to a line wire of the power supply cable, aneutral prong that is electrically connected to a neutral wire of thepower supply cable, and the first ground prong that is electricallyconnected to the first ground wire of the power supply cable. Thecombined plug also includes the second ground prong that is electricallyconnected to the second ground wire of the hydraulics grounding cable.

In some implementations, the first ground prong and the first groundwire are electrically isolated from the second ground prong and thesecond ground wire.

In some implementations, the first ground prong and the first groundwire are in electrical communication with the second ground prong andthe second ground wire via a connection that occurs behind a wall plateof the AC power outlet when the combined plug is plugged into the ACpower outlet.

In some implementations, the combined plug is a contiguous piece ofmaterial to which all prongs are connected.

In some implementations, the combined plug also includes non-conductiveprongs for improving an integrity of a connection between the combinedplug and the AC power outlet.

In some implementations, the combined plug includes a handle tofacilitate simultaneous connection of the power supply cable and thehydraulics grounding cable to the AC power outlet.

In some implementations, the first ground wire and the second groundwire do not share a common insulation.

In some implementations, the dialysis machine complies with one or morerequirements specified by a standards organization when the firstgrounding connection is connected to a first AC socket of an AC poweroutlet and the second grounding connection is connected to a second ACsocket of the AC power outlet.

In some implementations, the standards organization is the InternationalElectrotechnical Commission (IEC) and the one or more requirements arespecified in IEC 60364-7-710.

In some implementations, the hydraulics grounding cable is configured toplug into a grounding socket of the dialysis machine.

In some implementations, the grounding socket is in electricalcommunication with a metal chassis of the hydraulics system.

In some implementations, the dialysis machine is a hemodialysis (“HD”)machine.

In some implementations, the power supply cable and the hydraulicsgrounding cable electrically connect to the dialysis machine at separatelocations at the housing of the dialysis machine.

In another aspect, a plug that is configured to plug into an AC poweroutlet includes a power supply cable that includes a first ground wireelectrically connected to a first ground prong. The power supply cableis for providing power to a dialysis machine. The plug also includes ahydraulics grounding cable that includes a second ground wireelectrically connected to a second ground prong. The hydraulicsgrounding cable is for providing a grounding connection to a hydraulicssystem of the dialysis machine. The plug also includes a handle forfacilitating simultaneous connection of the power supply cable and thehydraulics grounding cable to an AC power outlet. The groundingconnection of the hydraulics system is separate and distinct from thefirst ground wire and the first ground prong of the power supply cable.

Implementations can include one or more of the following features.

In some implementations, the first ground prong and the first groundwire are electrically isolated from the second ground prong and thesecond ground wire.

In some implementations, the first ground wire and the second groundwire do not share a common insulation.

In some implementations, the plug also includes an adapter that isconfigured to removably connect to and form an electrical connectionwith the power supply cable, removably connect to and form an electricalconnection with the hydraulics grounding cable, and plug into the ACpower outlet.

Implementations can include one or more of the following advantages.

In some implementations, providing a separate grounding connection forthe hydraulics system allows the dialysis machine to meet requirementsspecified by a standards organization, such as the InternationalElectrotechnical Commission (IEC), and in particular, to meet therequirements of IEC 60364-7-710 and/or IEC 60601-2-16. The separategrounding connection helps to ensure that the patient's safety ismaintained by protecting the patient from leakage currents of anunacceptable magnitude.

In some implementations, the combined plug ensures that both groundingconnections are concurrently made. For example, in implementations inwhich the power supply cable and the hydraulics grounding cable do notshare a combined plug, an operator or technician may forget to plug thehydraulics grounding cable into the second AC socket. Forgetting toconnect the hydraulics grounding cable may be more likely because thehemodialysis machine may require only the power supply cable to beconnected in order to operate. In other words, the hemodialysis machinemay be able to operate without the hydraulics grounding cable beingconnected. Therefore, including the second end of the power supply cableand the second end of the hydraulics grounding cable as a combined plugmay ensure that both the first grounding connection and the secondgrounding connection are made simultaneously and/or maintainedconcurrently.

Other aspects, features, and advantages of the subject matter includedherein will be apparent from the description and drawings, and from theclaims.

DESCRIPTION OF DRAWINGS

FIG. 1A is a front perspective view of a hemodialysis machine.

FIG. 1B is a back perspective view of the hemodialysis machine thatshows two separate grounding connections.

FIG. 2 shows an example of a socket on the hemodialysis machine to whicha power supply cable is configured to connect.

FIG. 3 shows an exploded view of an AC power outlet and a combined plugthat is configured to be connected thereto.

FIG. 4 shows an example of the power supply cable being separate from ahydraulics grounding cable.

FIG. 5 is a block diagram of an example computer system.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

A medical device, such as a dialysis machine (e.g., a hemodialysismachine) may include multiple separate electrical grounding connections.For example, the dialysis machine may include a power supply thatincludes a first grounding connection (e.g., as part of an AC powerplug) and a separate system (e.g., a hydraulics system) that includes asecond grounding connection (e.g., a non-standard connection). The firstgrounding connection and the second grounding connection may includeseparate, distinct wires that each terminates at a separate groundinglocation. For example, the first grounding connection may terminate at aground (e.g., earth ground) of a first AC socket and the secondgrounding connection may terminate at a ground (e.g., earth ground) of asecond AC socket. The first and second AC sockets may be part of thesame AC power outlet. Therefore, the two earth grounds may beelectrically connected by wiring that resides behind a wall plate of theAC power outlet. In some implementations, while the two groundingconnections may be provided as separate, distinct wires (e.g., which maybe enclosed within separate cabling), the two grounding connections maybe incorporated as a single (e.g., combined) plug to ensure that bothgrounding connections are made substantially simultaneously and/ormaintained concurrently.

FIG. 1A shows a front perspective view of an example of a medical devicesuch as a hemodialysis machine 100. The hemodialysis machine 100includes, among other things, a blood circuit module 102 and ahydraulics system 104. In general, during hemodialysis, arterial andvenous patient lines of the blood circuit module 102 are connected to apatient and blood is circulated through various blood lines andcomponents, including a dialyzer. At the same time, dialysate iscirculated through a dialysate circuit formed by the dialyzer andvarious other dialysate components and dialysate lines connected to thehemodialysis machine 100. Many of these dialysate components anddialysate lines are located inside the housing of the hemodialysismachine 100, and are thus not visible in FIG. 1A.

The dialysate passes through the dialyzer along with the blood. Theblood and dialysate passing through the dialyzer are separated from oneanother by a semi-permeable structure (e.g., a semi-permeable membraneand/or semi-permeable microtubes) of the dialyzer. As a result of thisarrangement, toxins are removed from the patient's blood and collectedin the dialysate. The filtered blood exiting the dialyzer is returned tothe patient. The dialysate that exits the dialyzer includes toxinsremoved from the blood and is commonly referred to as “spent dialysate.”The spent dialysate is routed from the dialyzer to a drain. Whenultrafiltration is performed during treatment, a combination of thespent dialysate and excess fluid drawn from the patient is carried tothe drain via an ultrafiltration line.

The hemodialysis machine 100 includes a monitor in the form of a touchscreen 106. The touch screen 106 allows an operator to input varioustreatment parameters to the hemodialysis machine 100 and to otherwisecontrol the hemodialysis machine 100. In addition, the touch screen 106serves as a display. The touch screen 106 functions to provideinformation to the patient and the operator of the hemodialysis machine100. For example, the touch screen 106 may display information relatedto a dialysis treatment to be applied to the patient.

The hemodialysis machine 100 also includes a processing module thatresides inside the machine and which is configured to communicate withthe touch screen 106. The processing module is configured to receivedata from the touch screen 106 and control the hemodialysis machine 100based on the received data. For example, the processing module canadjust the operating parameters of the hemodialysis machine 100.

The components of the hemodialysis machine 100 that are responsible formaking, balancing, supplying, and draining the dialysate are generallyreferred to as the hydraulics system 104. The hydraulics system 104includes, among other things, the dialysate circuit (e.g., including thevarious dialysate lines, dialysate components, and the dialyzer) and abalancing chamber (e.g., where the volumes of fluid to and from thedialyzer are volumetrically balanced).

The hemodialysis machine 100 is generally powered by a power supply. Thepower supply may be configured to provide power to all components of thehemodialysis machine 100, including but not limited to the blood circuitmodule 102, the hydraulics system 104, and the touch screen 106. Thepower supply includes a grounding connection (e.g., as part of an ACpower plug). However, one or more components and/or systems of thehemodialysis machine 100 may include its own grounding connection. Forexample, the hydraulics system 104 may include a grounding connectionthat is separate from the grounding connection of the power supply thatis configured to separately ground the components that make up thehydraulics system 104. In this way, the grounding connection of thehydraulics system 104 provides a separate and distinct groundingconnection for the hydraulics system 104 (e.g., as opposed to providinga second, redundant, ground connection for the power supply).

In some implementations, the separate grounding connection for thehydraulics system 104 may be included at least in part to comply withstandards established by a standards organization. For example, thehemodialysis machine 100 may be configured and arranged to meet Class Iregulations and/or to comply with requirements specified by theInternational Electrotechnical Commission (IEC), in particular, with IEC60364-7-710.

IEC 60364-7-710 specifies that the following requirements must beobserved by the hemodialysis machine 100 when it is connected to an ACpower supply:

Power failures <20 ms;

A grounding system must be installed as prescribed;

A power socket with a protective earth connection is required;

The line cross-section and line lengths to the power socket must bedimensioned so as to ensure that the voltage tolerance and the functionof the protective devices is always guaranteed (recommended linecross-section to the power socket: at least 3×1.5 mm² copper core for220 V-240 V and at least 3×2.5 mm² copper core for voltages of less than220 V);

Each electric circuit is protected from damage through fault conditionswith an automatic, fast-acting circuit breaker (recommendation: 16 A at220 V-240 V and 20 A at voltages lower than 220 V);

No more than one device per wall socket and electric circuit;

The use of power strips and extension cables is prohibited;

Residual-current devices (RCDs) which protect against dangerous shockcurrents in the event of fault conditions (recommendation: one RCD(fault current less than 30 mA) for each device (or socket)); and

Overvoltage/lightning protection in the main and emergency power supplynetworks.

In some implementations, the separate grounding connection for thehydraulics system 104 may be included at least in part due to a leakagecurrent surpassing an acceptable limit. For example, IEC 60364-7-710(or, e.g., another standard) may specify that patient leakage currentsfor type CF applied parts (e.g., parts that are in direct conductivecontact with the heart or other applications as considered necessary)may not surpass 10 μA AC/DC for normal condition (e.g., no faultcondition) and 50 μA AC/DC for single fault condition. Failure toprovide the separate grounding connection may put the patient at risk(e.g., due to electric current of a dangerous magnitude running throughthe patient). If one or more of these conditions are not met by thehemodialysis machine 100, one option for alleviation may be theinclusions of the separate grounding connection for the hydraulicssystem 104.

In some implementations, the separate grounding connection for thehydraulics system 104 may be included at least in part to comply withrequirements and/or standards imposed by a particular country. Forexample, the hemodialysis machine 100 may be able to satisfy therequirements imposed by a first country without including separategrounding connections, but the hemodialysis machine 100 may be requiredto include separate grounding connections in order to satisfy therequirements of a second country. By including separate groundingconnections, the hemodialysis machine 100 may be sold worldwide (e.g.,rather than providing different versions of the hemodialysis machine 100to different countries).

FIG. 1B shows a back perspective view of the hemodialysis machine 100that shows separate grounding connections for the power supply and thehydraulics system 104. The power supply (the majority of which is notshown) is configured to generally supply power to the components of thehemodialysis machine 100, including the blood circuit module 102 (e.g.,including blood pumps), the hydraulics system 104 (e.g., includingdialysate pumps), the touch screen 106, the processing module, varioussensors, etc. The power supply includes a socket 108 that is configuredto accept a power supply cable 110. The power supply cable 110 residesoutside of the housing of the hemodialysis machine 100. The socket 108includes a plurality of electrical conductors that are configured tomate with corresponding electrical connections (e.g., wires) in thepower supply cable 110 when a first end of the power supply cable 110 isconnected to the socket 108. The socket 108 is partially obscured by thepower supply cable 110 in FIG. 1B due to the front view. Referringbriefly to FIG. 2 , examples of the socket 108 and the power supplycable 110 are shown. The socket 108 (shown in a perspective view)includes a line prong 202, a neutral prong 204, and a ground prong 206(e.g., earth ground), and the power supply cable 110 includes a linewire 212, a neutral wire 214, and a ground wire 216 (e.g., earthground). When the power supply cable 110 is plugged into the socket 108of the hemodialysis machine 100, the wires 212, 214, 216 areelectrically connected to the corresponding prongs 202, 204, 206 of thesocket 108.

A second end of the power supply cable 110 is configured to plug into apower outlet. In some implementations, the second end of the powersupply cable 110 may be part of a combined plug 130, as described inmore detail below with respect to FIG. 3 . In some implementations, thepower outlet is a standard AC power outlet such as one that isstandardized by the National Electrical Manufacturers Association(NEMA), such as a NEMA 5-15 grounded (Type B) outlet or a NEMA 5-20outlet. The second end of the power supply cable 110 includes a lineprong 112, a neutral prong 114, and a ground prong 116 (e.g., earthground) that are electrically connected to the corresponding wires 212,214, 216 of the power supply cable 110. The ground prong 116 and theground wire (216 of FIG. 2 ) of the power supply cable 110 collectivelyform a first grounding connection of the hemodialysis machine 100 forgrounding the power supply. When the second end of the power supplycable 110 is plugged into the power outlet, the prongs 112, 114, 116 ofthe power supply cable 110 are electrically connected to correspondingwires of the power outlet, as described in more detail below withrespect to FIG. 3 .

In addition to the first grounding connection (e.g., for grounding thepower supply), the hemodialysis machine 100 includes a second groundingconnection for the hydraulics system 104. The second groundingconnection is separate from the grounding connection of the power supplyand is configured to separately ground the components of the hydraulicssystem 104, including but not limited to the dialysate pumps.

The hemodialysis machine 100 includes a hydraulics grounding socket 118that is configured to accept a hydraulics grounding cable 120. Thehydraulics grounding cable 120 resides outside of the housing of thehemodialysis machine 100. The hydraulics grounding socket 118 includesan electrical conductor that is configured to mate with a correspondingelectrical connection (e.g., a wire) in the hydraulics grounding cable120 when a first end of the hydraulics grounding cable 120 is connectedto the hydraulics grounding socket 118. A second end of the hydraulicsgrounding cable 120 is configured to plug into a ground orifice (e.g.,earth ground) of a power outlet. In some implementations, the second endof the hydraulics grounding cable 120 may be part of the combined plug130, as described in more detail below with respect to FIG. 3 . In someimplementations, the power outlet is a standard AC power outlet such asone that is standardized by NEMA, such as a NEMA 5-15 grounded (Type B)outlet or a NEMA 5-20 outlet. The second end of the hydraulics groundingcable 120 includes a ground prong 122 (e.g., earth ground) that iselectrically connected to a corresponding ground wire (e.g., earthground) (360 of FIG. 3 ) of the hydraulics grounding cable 120. Theground prong 122 and the ground wire 360 of the hydraulics groundingcable 120 collectively form the second grounding connection of thehemodialysis machine 100 for grounding the hydraulics system 104. Whenthe second end of the hydraulics grounding cable 120 is plugged into thepower outlet, the ground prong 122 of the hydraulics grounding cable 120is electrically connected to a corresponding ground wire of the poweroutlet, as described in more detail below with respect to FIG. 3 .

The hydraulics grounding socket 118 may be incorporated into a chassisof the hydraulics system 104. For example, the components of thehydraulics system 104 may be arranged in a chassis (e.g., a metalchassis), and the hydraulics grounding socket 118 may be electricallyconnected to the metal chassis (and, e.g., the electrical components ofthe hydraulics system 104). In this way, the second grounded connectionprovided at least in part by the hydraulics grounding cable 120 mayprovide a separate grounding connection for the electrical components ofthe hydraulics system 104 that is distinct from the grounding connection(e.g., the first grounding connection) of the power supply.

In some implementations, the locations on the hemodialysis machine 100from where the first and second grounding connections emanate may beseparated by a particular (e.g., predetermined) distance. In otherwords, the power supply cable 110 and the hydraulics grounding cable 120may be electrically connected to the hemodialysis machine 100 atseparate locations at the housing of the hemodialysis machine 100 thatare separated by a particular distance. For example, the power supplysocket 108 and the hydraulics grounding socket 118 may be separated by apredetermined distance of approximately 1-5 feet. In this way, the firstand second grounding connections are spatially separated from each otheroutside of the housing of the hemodialysis machine 100 (e.g., due to thetwo distinct locations on the hemodialysis machine 100 from where thefirst and second grounding connections emanate). In someimplementations, separation of the power supply socket 108 and thehydraulics grounding socket 118 may contribute to the separate anddistinct nature of the two grounding connections.

FIG. 3 shows an exploded view of an AC power outlet 300 that isconfigured to electrically connect to the power supply cable 110 and thehydraulics grounding cable 120 (e.g., by accepting the prongs 112, 114,116, 122 of the power supply cable 110 and the hydraulics groundingcable 120). The AC power outlet 300 includes a first AC socket 310 and asecond AC socket 320 positioned beneath the first AC socket 310. Thefirst AC socket 310 includes a line contact 312, a neutral contact 314,and a ground contact 316 (e.g., earth ground), and the second AC socket320 includes a line contact 322, a neutral contact 324, and a groundcontact 326 (e.g., earth ground). The AC power outlet 300 includes aline terminal 332 to which the line contacts 312, 322 are electricallyconnected (e.g., by wires shown in dotted lines), a neutral terminal 334to which the neutral contacts 314, 324 are electrically connected (e.g.,by wires shown in dotted lines), and a ground terminal 336 (e.g., earthground) to which the ground contacts 316, 326 are electrically connected(e.g., by wires shown in dotted lines). A line wire 342 is connected tothe line terminal 332, a neutral wire 344 is connected to the neutralterminal 334, and a ground wire 346 (e.g., earth ground) is connected tothe ground terminal 336. The wires 342, 344, 346 may be connected,respectively, to a line bus, a neutral bus, and a ground bus (e.g.,earth ground) of a power supply of the building in which the AC poweroutlet 300 resides.

The ground contact 316 of the first AC socket 310 and the ground contact326 of the second AC socket 320 are electrically connected to the groundterminal 336 of the AC power outlet 300 by wires, shown as dotted linesin FIG. 3 . Therefore, while the two ground contacts 316, 326 make upseparate and distinct electrical connection points, the two groundcontacts 316, 326 are electrically connected to each other at the groundterminal 336 behind a wall plate 350 of the AC power outlet 300.Nonetheless, because the two grounding connections (e.g., the firstgrounding connection formed by the ground prong 116 and the ground wire216 of the power supply cable 110, and the second grounding connectionformed by the ground prong 122 and the ground wire 360 of the hydraulicsgrounding cable 120) terminate at two different ground contacts 316, 326of two different AC sockets 310, 320, the standards with which thehemodialysis machine 100 must comply (e.g., IEC 60364-7-710) aresatisfied. For example, with respect to at least IEC 60364-7-710, thereis no requirement for the two separate grounding connections to beconnected to separate power outlets. In fact, connecting the twoseparate grounding connections to separate power outlets may havenegative consequences (e.g., the creation of significant differences incurrent). Therefore, it may be advisable to connect both groundingconnections to the same AC power outlet 300, albeit to different ACsockets 310, 320, assuming the wiring of the AC power outlet 300 isappropriately arranged.

In some implementations, the two grounding connections may beelectrically connected within the dialysis machine 100 (e.g., via commonpaths through the chasses and/or shared electronic components). In someimplementations, the separate grounding connections meeting in onecommon location (e.g., behind the wall plate 350 of the AC power outlet300) can be beneficial because the common location has the sameelectrical potential (e.g., lower electrical potential) for each of theseparate grounding connections to facilitate redundancy (e.g., completeredundancy) in the grounding connections.

In some implementations, the AC power outlet 300 may include a built-infuse and/or a testing feature that can ensure the continued integrity ofthe electrical connection. For example, the AC power outlet 300 mayinclude an indicator (e.g., a visual indicator in the form of a light)that is configured to provide an indication (e.g., by lighting and/orflashing the light) when one or both of the ground prong 122 of thehydraulics grounding cable 120 and the ground prong 116 of the powersupply cable 110 are not connected to their respective ground contacts316, 326. In some implementations, the ground prongs 116, 122 are longerthan the line prong 112 and the neutral prong 114 to ensure propergrounding before electrical current enters the hemodialysis machine 100.

As briefly described above with respect to FIG. 1B, one or both of thesecond end of the power supply cable 110 and the second end of thehydraulics grounding cable 120 may be part of a single combined plug130. The combined plug 130 is a single, contiguous structure thatincludes an upper portion and a lower portion. The upper portioncorresponds to the power supply cable 110 and the lower portioncorresponds to the hydraulics grounding cable 120. That is, the secondend of the power supply cable 110, including the line prong 112, theneutral prong 114, and the ground prong 116, forms the upper portion ofthe combined plug 130, and the second end of the hydraulics groundingcable 120, including the ground prong 122, forms the lower portion ofthe combined plug 130.

The combined plug 130 also includes a handle 370 that is arrangedsubstantially between the upper and lower portions. The handle 370 isconfigured to facilitate connection/disconnection of the combined plug130 to/from the AC power outlet 300. An individual can simultaneouslyconnect/disconnect all of the prongs 112, 114, 116, 122 of the combinedplug 130 to/from the AC power outlet 300 in one motion by applyingpressure to the handle 370. In some implementations, the combined plug130 also includes a recess on a surface of the combined plug 130 thatmakes contact with the wall plate 350 when the combined plug 130 isconnected to the AC power outlet 300. The recess allows a screw affixedto the wall plate 350 to fit therein such that the combined plug 130 canrest evenly against the wall plate 350 when the combined plug 130 isconnected to the AC power outlet 300, thereby maintaining the integrityof the connection without disruption.

The combined plug 130 ensures that both grounding connections areconcurrently made. For example, in implementations in which the powersupply cable 110 and the hydraulics grounding cable 120 do not share acombined plug 130, an operator or technician may forget to plug thehydraulics grounding cable 120 into the second AC socket 320. Forgettingto connect the hydraulics grounding cable 120 may be more likely becausethe hemodialysis machine 100 may require only the power supply cable 110to be connected in order to operate. In other words, the hemodialysismachine 100 may be able to operate (e.g., albeit potentially unsafely)without the hydraulics grounding cable 120 being connected. Therefore,including the second end of the power supply cable 110 and the secondend of the hydraulics grounding cable 120 as a combined plug 130 mayensure that both the first grounding connection and the second groundingconnection are made simultaneously and/or maintained concurrently.

The first grounding connection (e.g., formed by the ground prong 116 andthe ground wire 216 of the power supply cable 110) is sometimes referredto as a standard grounding connection. In other words, the firstgrounding connection is provided by a ground prong and wire that istypically found in a standard AC power cable that also includes a lineprong and a neutral prong. The second grounding connection (e.g., formedby the ground prong 122 and the ground wire 360 of the hydraulicsgrounding cable 120) is sometimes referred to as a non-standardgrounding connection. In other words, the second grounding connection isprovided by a ground prong that is typically not separately provided(e.g., without a corresponding line prong and neutral prong) in a cablethat is to be connected to an AC socket. The second, non-standardgrounding connection provides a solution to the leakage current concernsdescribed above that is specifically tailored to help ensure safeoperation of the hemodialysis machine 100.

Still referring to FIG. 3 , the power supply cable 110 includes the linewire 212, the neutral wire 214, and the ground wire 216. Each of thewires 212, 214, 216 has its own insulation. All of the wires 212, 214,216 are collectively enclosed within a common insulation, for example,the insulation of the power supply cable 110. The hydraulics groundingcable 120 includes the ground wire 360, which has its own insulation andwhich is also enclosed in the insulation of the hydraulics groundingcable 120.

As described above, the first and second grounding connections areseparate and distinct in that they terminate at two different groundcontacts 316, 326 of two different AC sockets 310, 320. The first andsecond grounding connections are also separate and distinct in thattheir respective ground wires 216, 360 are included within separateinsulations (e.g., cables) and therefore do not share a commoninsulation. In other words, the first and second grounding connectionsare separate and distinct in that they are not included as part of acommon cable (e.g., either the power supply cable 110 or the hydraulicsgrounding cable 120).

In some implementations, the second grounding connection terminates atthe ground contact 326 of the second AC socket 320. In other words, thesecond grounding connection may provide grounding for the hydraulicssystem 104 of the hemodialysis machine 100 without providing a furtherelectrical path to other portions of the hemodialysis machine 100 (or,e.g., to other devices). In some implementations, the second groundingconnection is a power grounding connection (e.g., as opposed to agrounding connection for a non-powered line, such as a data line).

While certain implementations have been described, other implementationsare possible.

While the power supply cable and the hydraulics grounding cable havebeen described as being part of a single combined plug, otherconfigurations are possible. FIG. 4 shows an example in which the powersupply cable 110 and the hydraulics grounding cable 120 are separate.That is, the second end of the power supply cable 110 includes a plug402 and the second end of the hydraulics grounding cable 120 includes aseparate plug 404. Each of the plugs 402, 404, is configured toseparately plug into an AC socket. In this way, the ground prongs 116,122 are included in separate plugs 402, 404.

In some implementations, providing separate plugs 402, 404 for the powersupply cable 110 and the hydraulics grounding cable 120 allows the powersupply cable 110 to be plugged into an AC socket that belongs to a firstAC power outlet and the hydraulics grounding cable 120 to be pluggedinto an AC socket that belongs to a different (e.g., separate) AC poweroutlet. However, as described above, in some implementations, connectingthe power supply cable 110 and the hydraulics grounding cable 120 todifferent AC power outlets may be undesirable in some cases.

In some implementations, the plug 404 of the hydraulics grounding cable120 includes non-conductive prongs 406 for improving and/or ensuring theintegrity of the connection between the plug 404 and the AC socket. Insome implementations, the non-conductive prongs 406 are made of apolymer (e.g., plastic).

While the combined plug has been described as being a single contiguousstructure (e.g., such that the second ends of the power supply cable andthe hydraulics grounding cable are permanently connected to each other),in some implementations, the combined plug may be an adapter that isconfigured to combine the power supply cable and the hydraulicsgrounding cable. For example, the adapter may include an upper portionthat corresponds to the power supply cable and a lower portion thatcorresponds to the hydraulics grounding cable. The upper portion mayinclude a socket that includes a line contact, a neutral contact, and aground contact (e.g., earth ground) that is configured to accept theprongs of the power supply cable. The socket may be arranged similar tothat which is typically seen in a standard AC socket. The upper portionmay also include a line prong, a neutral prong, and a ground prong(e.g., earth ground) that form electrical connections with the wires ofthe power supply cable when the power supply cable is plugged into theupper socket. Similarly, the lower portion may include a socket thatincludes a ground contact (e.g., earth ground) that is configured toaccept the ground prong of the hydraulics grounding cable. The lowerportion may also include a ground prong (e.g., earth ground) that formsan electrical connection with the ground wire of the hydraulicsgrounding cable when the hydraulics grounding cable is plugged into thelower socket. The prongs of the adapter may be plugged into an AC poweroutlet to provide power to the hemodialysis machine while ensuringproper grounding.

In some implementations, the adapter has a handle similar to that whichis described above with respect to FIG. 3 . Using an adapter as thecombined plug (e.g., as opposed to the second ends of the power supplycable and the hydraulics grounding cable being permanently connected)can allow the cables to be disconnected for easier storage. Further, ifone or more of the adapter, the power supply cable, and the hydraulicspower cable are damaged, the damaged component can be replaced withoutrequiring replacement of the other non-damaged components.

While the first grounding connection has been described as beingcollectively formed by the ground prong and the ground wire of the powersupply cable, in some implementations, one or more portions of the firstAC socket can also be considered part of the first grounding connection.For example, the ground contact of the first AC socket may be part ofthe first grounding connection. Similarly, while the second groundingconnection has been described as being collectively formed by the groundprong and the ground wire of the hydraulics grounding cable, in someimplementations, one or more portions of the second AC socket can alsobe considered part of the second grounding connection. For example, theground contact of the second AC socket may be part of the secondgrounding connection.

While the hydraulics system has been described as including a balancingchamber, in some implementations, the hydraulics system does not includea balancing chamber. In some implementations, the hydraulics system mayinclude one or more pumps for circulating dialysate through thedialysate circuit.

While the systems and techniques have been largely described withreference to a hemodialysis machine, other types of medical devices andmedical treatment systems may also utilize the grounding techniques anddevices described herein. Examples of other medical treatment systemsthat may employ the techniques described herein include peritonealdialysis systems, hemofiltration systems, hemodiafiltration systems,apheresis systems, and cardiopulmonary bypass systems.

In some implementations, the medical device is a system that isconfigured for use with a patient for diagnostic and/or therapeuticpurposes. The medical device may generally include two sets ofcomponents. In some examples, the medical device includes a first set ofcomponents that are configured to connect to and/or make contact withthe patient, and a second set of components that are configured tofacilitate other functionality of the medical device. Such a medicaldevice may include multiple separate electrical grounding connectionsfor each set of components.

The separate grounding connections may be substantially similar to theseparate grounding connections described above with respect to FIGS. 1-4. For example, the medical device may include a power supply (e.g., forgenerally providing power to the medical device) that includes a firstgrounding connection, and a patient treatment system (e.g., thatphysically and/or electrically connects to the patient) that includes aseparate, second grounding connection. The second, separate groundingconnection may include a patient grounding cable that includes a groundwire (e.g., a separate ground wire than the ground wire of the powersupply). The first grounding connection and the second groundingconnection may include separate, distinct wires that each connects to aseparate location at the medical device (e.g., at different locations ata housing of the medical device). The first and second groundingconnections may terminate at respective grounds (e.g., earth grounds) oftwo separate AC power sockets. In some implementations, while the twogrounding connections may be provided as separate, distinct wires (e.g.,which may be enclosed within separate cabling), the two groundingconnections may be incorporated as a single (e.g., combined) plug toensure that both grounding connections are made substantiallysimultaneously and/or maintained concurrently.

FIG. 5 is a block diagram of an example computer system 500. Forexample, the processing module described with respect to FIG. 1A couldbe an example of the system 500 described here. The system 500 includesa processor 510, a memory 520, a storage device 530, and an input/outputdevice 540. Each of the components 510, 520, 530, and 540 can beinterconnected, for example, using a system bus 550. The processor 510is capable of processing instructions for execution within the system500. The processor 510 can be a single-threaded processor, amulti-threaded processor, or a quantum computer. The processor 510 iscapable of processing instructions stored in the memory 520 or on thestorage device 530. The processor 510 may execute operations such ascausing the dialysis system to carry out functions related to a dialysistreatment.

The memory 520 stores information within the system 500. In someimplementations, the memory 520 is a computer-readable medium. Thememory 520 can, for example, be a volatile memory unit or a non-volatilememory unit. In some implementations, the memory 520 stores informationrelated to a treatment to be administered to a patient.

The storage device 530 is capable of providing mass storage for thesystem 500. In some implementations, the storage device 530 is anon-transitory computer-readable medium. The storage device 530 caninclude, for example, a hard disk device, an optical disk device, asolid-date drive, a flash drive, magnetic tape, or some other largecapacity storage device. The storage device 530 may alternatively be acloud storage device, e.g., a logical storage device including multiplephysical storage devices distributed on a network and accessed using anetwork. In some implementations, the information stored on the memory520 can also or instead be stored on the storage device 530.

The input/output device 540 provides input/output operations for thesystem 500. In some implementations, the input/output device 540includes one or more of network interface devices (e.g., an Ethernetcard), a serial communication device (e.g., an RS-232 10 port), and/or awireless interface device (e.g., a short-range wireless communicationdevice, an 802.11 card, a 3G wireless modem, or a 4G wireless modem). Insome implementations, the input/output device 540 includes driverdevices configured to receive input data and send output data to otherinput/output devices, e.g., a keyboard, a printer, and display devices(such as the touch screen 106). In some implementations, mobilecomputing devices, mobile communication devices, and other devices areused.

In some implementations, the system 500 is a microcontroller. Amicrocontroller is a device that contains multiple elements of acomputer system in a single electronics package. For example, the singleelectronics package could contain the processor 510, the memory 520, thestorage device 530, and input/output devices 540.

Although an example processing system has been described in FIG. 5 ,implementations of the subject matter and the functional operationsdescribed above can be implemented in other types of digital electroniccircuitry, or in computer software, firmware, or hardware, including thestructures disclosed in this specification and their structuralequivalents, or in combinations of one or more of them. Implementationsof the subject matter described in this specification can be implementedas one or more computer program products, i.e., one or more modules ofcomputer program instructions encoded on a tangible program carrier, forexample a computer-readable medium, for execution by, or to control theoperation of, a processing system. The computer readable medium can be amachine readable storage device, a machine readable storage substrate, amemory device, a composition of matter effecting a machine readablepropagated signal, or a combination of one or more of them.

The term “computer system” may encompass all apparatus, devices, andmachines for processing data, including by way of example a programmableprocessor, a computer, or multiple processors or computers. A processingsystem can include, in addition to hardware, code that creates anexecution environment for the computer program in question, e.g., codethat constitutes processor firmware, a protocol stack, a databasemanagement system, an operating system, or a combination of one or moreof them.

A computer program (also known as a program, software, softwareapplication, script, executable logic, or code) can be written in anyform of programming language, including compiled or interpretedlanguages, or declarative or procedural languages, and it can bedeployed in any form, including as a standalone program or as a module,component, subroutine, or other unit suitable for use in a computingenvironment. A computer program does not necessarily correspond to afile in a file system. A program can be stored in a portion of a filethat holds other programs or data (e.g., one or more scripts stored in amarkup language document), in a single file dedicated to the program inquestion, or in multiple coordinated files (e.g., files that store oneor more modules, sub programs, or portions of code). A computer programcan be deployed to be executed on one computer or on multiple computersthat are located at one site or distributed across multiple sites andinterconnected by a communication network.

Computer readable media suitable for storing computer programinstructions and data include all forms of non-volatile or volatilememory, media and memory devices, including by way of examplesemiconductor memory devices, e.g., EPROM, EEPROM, and flash memorydevices; magnetic disks, e.g., internal hard disks or removable disks ormagnetic tapes; magneto optical disks; and CD-ROM and DVD-ROM disks. Theprocessor and the memory can be supplemented by, or incorporated in,special purpose logic circuitry. The components of the system can beinterconnected by any form or medium of digital data communication,e.g., a communication network. Examples of communication networksinclude a local area network (“LAN”) and a wide area network (“WAN”),e.g., the Internet.

A number of implementations of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other implementations are within the scope of the followingclaims.

What is claimed is:
 1. A medical device comprising: a power supply forpowering the medical device, the power supply including a power supplycable that includes a first ground wire electrically connected to afirst ground prong; and a treatment system that is configured to bephysically or electrically connected to a patient for medically treatingthe patient, the treatment system including a grounding cable thatincludes a second ground wire electrically connected to a second groundprong.
 2. The medical device of claim 1, wherein the first ground prongand the first ground wire are electrically isolated from the secondground prong and the second ground wire.
 3. The medical device of claim1, wherein the power supply cable and the grounding cable are connectedto a combined plug that is configured to plug into an AC power outlet.4. The medical device of claim 3, wherein the combined plug comprises: aline prong that is electrically connected to a line wire of the powersupply cable, a neutral prong that is electrically connected to aneutral wire of the power supply cable, and the first ground prong thatis electrically connected to the first ground wire of the power supplycable; and the second ground prong that is electrically connected to thesecond ground wire of the grounding cable.
 5. The medical device ofclaim 4, wherein the first ground prong and the first ground wire areelectrically isolated from the second ground prong and the second groundwire.
 6. The medical device of claim 4, wherein the first ground prongand the first ground wire are in electrical communication with thesecond ground prong and the second ground wire via a connection thatoccurs behind a wall plate of a AC power outlet when the combined plugis plugged into the AC power outlet.
 7. The medical device of claim 4,wherein the combined plug is a contiguous piece of material to which allprongs are connected.
 8. The medical device of claim 4, wherein thecombined plug further comprises non-conductive prongs for improving anintegrity of a connection between the combined plug and a AC poweroutlet.
 9. The medical device of claim 3, wherein the combined plugincludes a handle to facilitate simultaneous connection of the powersupply cable and the grounding cable to a AC power outlet.
 10. Themedical device of claim 1, wherein the first ground wire and the secondground wire do not share a common insulation.
 11. The medical device ofclaim 1, wherein the first ground wire and the first ground prong form afirst grounding connection, and the second ground wire and the secondground prong form a second grounding connection.
 12. The medical deviceof claim 11, wherein the first grounding connection is separate anddistinct from the second grounding connection.
 13. The medical device ofclaim 11, wherein the medical device complies with one or morerequirements specified by a standards organization when the firstgrounding connection is connected to a first AC socket of an AC poweroutlet and the second grounding connection is connected to a second ACsocket of the AC power outlet.
 14. The medical device of claim 13,wherein the standards organization is the International ElectrotechnicalCommission (IEC) and the one or more requirements are specified in IEC60364-7-710.
 15. The medical device of claim 1, wherein the groundingcable is configured to plug into a grounding socket of the medicaldevice.
 16. The medical device of claim 15, wherein the grounding socketis in electrical communication with a metal chassis of the treatmentsystem.
 17. The medical device of claim 1, wherein the medical device isa hemodialysis (“HD”) machine.
 18. The medical device of claim 1,wherein the power supply cable and the grounding cable electricallyconnect to the medical device at separate locations at a housing of themedical device.
 19. The medical device of claim 1, further comprising anadapter configured to: removably connect with the power supply cable;removably connect with the grounding cable; and plug into an AC poweroutlet.
 20. The medical device of claim 1, wherein the treatment systemis a hydraulic system.